A seat layout changeable configuration for a passenger car's rear seat or other vehicle seat is known in which a seat cushion is frontwardly tipped up and thereafter a seat back is frontwardly tilted down so that a storage space in a rear portion of the vehicle is enlarged. In such a vehicle seat, a configuration provided in order that a seat cushion, a seat back and a head rest can be moved into retracted positions with a simple operation is known in the art (see Patent literature 1), wherein a seat back reclining mechanism is unlocked by a first interlocking mechanism which operates in synchronization with a tip-up motion of the seat cushion, and a head rest is then unlocked by a second interlocking mechanism which operates in synchronization with a frontward tilt-down motion of the seat back to allow the head rest to be tilted down into its retracted position.
On the other hand, Patent literature 2 discloses a car seat configured to have a seat back frontwardly tilted down at the same time when the a seat cushion is raised, wherein a damper is provided in a rotatory motion mechanism of the seat back in order to avoid interference between the seat cushion and the seat back.